Why does the car shake when driving?
4 Answers
The most common causes of car shaking are a dirty throttle body or excessive carbon buildup in the fuel injectors. Here is relevant information: 1. When there is too much carbon buildup inside the engine, the gasoline sprayed by the cold-start injector will be largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold starts and making it difficult to start. 2. In this situation, the engine will only start easily once the carbon deposits have absorbed enough gasoline to become saturated. After starting, the gasoline adsorbed on the carbon deposits will be drawn into the cylinders by the engine's vacuum suction and burned, making the air-fuel mixture too rich. The combustible mixture in the engine alternates between being too lean and too rich, causing idle shaking after a cold start. 3. Additionally, for an engine to start, three essential and indispensable factors are required: fuel, air, and spark. If any of these three factors is obstructed or not functioning smoothly, the engine's operation will become unstable, and shaking will occur as a result.
I've experienced car shaking before. That time on the highway, I noticed the steering wheel kept vibrating, which scared me into heading straight to the repair shop. The technician said it was most likely a tire balance issue, and sure enough, when they took the wheel off, there was a big chunk of mud stuck to the inside of the rim. Things like unbalanced wheels, tire bulges, or unstable tire pressure can all cause this kind of shaking. If the car shakes even when parked, it might be due to aging engine mount bushings—when the rubber cracks, it can't absorb vibrations anymore. Worn drive shafts are another hidden culprit, especially noticeable during hard acceleration. If you notice shaking, don't ignore it; getting it checked early is better for peace of mind, especially since it's a safety issue.
Last week when I dropped my sister off at driving school, her training car was shaking like a massage chair. The mechanic said this kind of rhythmic vibration is most likely caused by a damaged CV joint, especially if there's a creaking sound when turning. Actually, warped brake rotors can also cause shaking - high-frequency steering wheel vibration when braking is a telltale sign. I remember one time after washing the car, the rims froze and the whole body shook when driving. It's recommended to first check the most problematic components like tires and rims, then inspect the chassis components. Daily parking habits matter too - constantly scraping the curb often leads to CV axle deformation.
There are two types of vibrations: whole-body wobbling and steering wheel shaking. For steering wheel shake, check the front wheel balancing first—it can be fixed for just 20 bucks. If it shakes only when braking, it's likely the brake discs warped from high heat, requiring resurfacing or replacement. As for idle vibration accompanied by an engine warning light, it's probably a misfire—either a spark plug or ignition coil has failed. Once I used the wrong fuel and it shook like a tractor; cleaning the fuel system fixed it. These common issues can be diagnosed at a repair shop in half an hour.
